Remote or Large workforces are much the same in this regard, the point of the email is simply to open communications, sometimes everyone will ignore it, sometimes the enthusiastic few will respond, those who respond will reflect the culture of the workplace just as much as your response will.
What is important in a Remote scenario is how you use this email as your tool for getting to know the key stakeholders in the workforce.
Delay replying
The answer from iBug is 100% spot on for this, but so is the advice from Freiheit, your response will likely end the end of this email chain, more importantly it signals the end of your "settling" in phase. Give everyone time across different timezones a chance to reach out to you, after all this is an informal exchange so it won't be hugh on their priority list yet. When you respond it will be informally accepted that you are "ready for work".
- If you don't receive a lot of responses, or any right away, give it a few hours, but that in itself will be a reflection of the culture, its not a bad thing, it just is how it is, so if there is no response and you think it has been a reasonable passage of time for them to respond, then maybe it's just not how they do things, then you should reply to show you are not ignoring your supervisor... that is also important!
Setup your email signature.
In a remote role your first email sent to everyone is important for a number of reasons, no more so than just like plugging into the matrix, your first response will be your projection of your "Digital Self"
After getting a few responses you should get a feel for the general culture of the team, make sure your email signature matches those of other people who are working in a similar position. If there have been no examples to copy, which will be normal, most people don't include a signature on a reply, then copy the signature from your supervisor.
If you think about how remote workforces interact, you are likely to have some IM platform that will have a profile, that might be your O365, GSuite, GitHub profile or something else. Make sure this is setup, if no such things have been communicated to you then your email signature is all you've got, when everyone needs to find you, they'll do a search in their inbox and your signature will tell them how to communicate with you.
If you want to be contacted via phone or IM then include your phone number or handle. What is appropriate here is up to you, but if you put your phone number you are pretty much broadcasting to everyone that you want them to use it.
Content
As for the content of your message, a simple warm or positive response is all that is needed. For everyone else though, this is your first impression and you get one shot at that, so keep it brief but get some personality in there. I would avoid any "in-jokes" because lets face it, you're not quite "in" yet. If this is an international organisation then you should use localised terms, especially if you think they would be internationally recognisable, I would also encourage injecting any cultural references that you feel are important. For those too lazy to look elsewhere, your response is all they know about you and for good or bad, will be their only reference when they do need to communicate with you.
Be approachable and Humble
As listed above, for everyone else, the email from your supervisor, and your response probably makes up 99% of what they know about you. Its not just facts though, its the inference too. A formal, flowery and long-winded response is boring, no one will read it, and you can guess what they will think of you... A one liner will be similar.
You want the recipient to feel like they could contact you if they needed to. They may never need to, but you certainly don't want to alienate the other existing and perhaps long standing members of the team, especially those whose aspirations you may have trampled by accepting the position. So be Humble, thank everyone and talk to how you will try to meet their high standards.
- The one exception to this is where your role is specifically to improve everyone else, even in this situation you will not win any friends by being condescending.
Who are you, to them?
Put yourself in the recipient's shoes, they get 50 emails a day, so they don't want to have to scroll through your life story, they want an at-a-glance view of who you are and what you mean to them. In the workplace this means roles and responsibilities. You should be very aware of what these are as part of the recruitment/employment process. If you are not, or if your role is ambiguous, this is your one shot to set the record straight.
For traditional roles putting the position in your email signature is usually enough, for some more obscure or non-traditional or more specific roles, it may help if you can
What is your availability
Again with the profile elements, but in a remote workplace this can be crucial.
This is an example of someone who just came to mind:
G'day Team!
Thanks for your warm welcomes, I'm excited to be a part of this team and I'm looking forward meeting everyone in the upcoming weeks.
If you need me urgently I'm always on Teams. After work you'll find me out the back playing basketball with my kids, or the dogs, but they're not too good at it yet...
Cheers!
Quirky Toad
.Net Technical Lead
Really Cool Software
Melbourne, Australia (UTC+10)
The key here is that it fits in most small email preview panes and still captures some personality and hobbies in a conversational tone, instead of sending a bullet list of your attributes. Pick one or two topics, what you show here will be perceived to be the most important things to you, whether they are or not is up to you, but for everyone else, it is clear that these topics are OK to talk about in public and will form the basis of small talk when we get to those awkward pauses in online meetings and your supervisor can't figure out how to approve the stragglers in from the lobby.
