I am a newbie in a professional world and hence I have some new friends in my working area including some seniors.
So, we are also connected from a social networking site but the issues is I am connected to all the professional friends via my personal social networking id so that they can see my the my personal spaces also there.
Should there be a different id for all my professional contacts?
Almost definitely you should try to keep them separate. Unless you never post anything on your personal social-network accounts that you wouldn't want your professional contacts to see. For most people that is not the case. In fact there have been a number of high-profile stories about people being fired after a professional contact discovered "inappropriate" content on their personal social-network account. You don't want to be that guy.
And conversely, content that would be appropriate for your professional contacts might be boring as hell to your personal friends. You don't want to be that guy who bores his friends by posting his work stuff on his personal social networks, either.
I'd suggest that there is a natural solution to this problem. Social networks targeted to professionals exist. Use one (like linkedin) for all of your professional contacts. Use another (like facebook) for all of your personal contacts. Note that some crossover may exist, and of course you should be particularly careful about letting a professional contact cross over into your personal social network. Make sure you know and trust the person and that you have a good relationship with them first. There's less risk with respect to letting personal contacts cross over into your professional network.
Personally I take a different approach...
I utilize social networking and media systems with the understanding that everything on the Internet is searchable and archived. Essentially if I don't want my boss to potentially learn something about me I simply don't post it.
I know this may seem restrictive to some, especially those of you who have grown up with technology such as myself. However, the realization is that to provide and create a professional reputation there is NO difference between personal and professional contacts.
For instance, your neighbors and family friends may not necessarily be viewed as professional contacts but when things are tough or you are looking for something new, they are often the first people you reach out to. Your friends need to know you are a good friend but they also need to know that if asked to recommend you for a job you are also a true professional.
So in my opinion no, use a single account. Just make sure you know what the implications are if you post a drunken picture of your latest spring break trip with the buds. This entire concept also goes back to a central idea of providing a personal brand for yourself.
It is nearly impossible to completely separate professional and personal contacts. What happens when a friend comes to work at your company? What happens when you and some coworkers start hanging out together a lot and become friends?
Instead of trying to maintain separate identities, I recommend having one identity and moderating what you post. First, as Brent pointed out, anything you post on the Internet is public, so remember that when considering those compromising photos from that party you only barely remember. Second, instead of separate identities, use filters -- security groups, circles, whatever your social network calls them, decide which of your friends/followers/contacts can see what content and only make the safe stuff visible to the world. If your social network doesn't support security groups, get one that does -- there's really no excuse not to have that feature these days.
Remember, though, that rule 1 still applies -- you've posted something to the Internet, albeit under lock, and a single weak link -- that is, one gossipy member of a security group, or one person you've had a falling-out with -- stands between your secret and a wider audience.
I try very hard to separate my online networks. You can use e.g. Facebook for your personal friends and LinkedIn for your professional contacts. Or you can use the segmentation features offered by some networks where you can organize contacts into groups and control who sees what.
Ultimately, it's up to you. Do you feel that your private persona and professional persona are similar enough that you can mix them freely? Does your personal social network contain anything that might reflect negatively on your professional persona? And remember, it's not just you that post on your social network, it's all your friends and contacts as well.
