In my experience (tech companies of various sizes, US):

• Things that are work-related and still useful are offered fairly routinely. People either leave it in the lunchroom with a note or keep it at their desks and send email. Items left in the lunchroom usually get removed (if not claimed) in a day or two. Don't let your unwanted items overstay their welcome in public places.

• Small gadgets that are still useful (e.g. you upgraded your Roku player) can be treated similarly. Large gadgets (e.g. you upgraded your TiVo) are generally offered via email or wiki post or lunch-time conversation and brought in only if someone wants them.

• Housewares and personal items (like clothing) pretty much aren't offered in most places. A coworker did once bring in a candelabra, accompanied by a note with an entertaining story about how he came to be trying to pass it along to a good home, but it was unusual. Exception: if your company is small and informal and has lots of people who are just getting established in life (e.g. furnishing their first apartments after graduating), this could be ok. If you don't know, though, I'd wait to see what other people do first.

• Very occasionally, larger amounts of other items are mentioned via email. For example, a coworker once inherited a relative's large collection of SF paperbacks, didn't want them personally, and thought others would be interested because we talked about SF a lot. This was a "you're welcome to come to my house, look through boxes, and take away anything you like" offer.

Only offer to pass along things that you can reasonably believe your coworkers would find valuable. Otherwise, there are charities that will be happy to accept donations of usable items and put them to use helping other people.

In my experience (tech companies of various sizes, US):

• Things that are work-related and still useful (books, laptop bags, keyboards, etc) are offered fairly routinely. People either leave it in the lunchroom with a note or keep it at their desks and send email. Items left in the lunchroom usually get removed (if not claimed) in a day or two. Don't let your unwanted items overstay their welcome in public places.

• Small gadgets that are still useful (e.g. you upgraded your Roku player) can be treated similarly. Large gadgets (e.g. you upgraded your TiVo) are generally offered via email or wiki post or lunch-time conversation and brought in only if someone wants them.

• Housewares and personal items (like clothing) pretty much aren't offered in most places. A coworker did once bring in a candelabra, accompanied by a note with an entertaining story about how he came to be trying to pass it along to a good home, but it was unusual. And I once brought in a new EFF t-shirt that was the wrong size for me, because the EFF is a widely-supported organization in that workplace. Exception: if your company is small and informal and has lots of people who are just getting established in life (e.g. furnishing their first apartments after graduating), this could be ok. If you don't know, though, I'd wait to see what other people do first.

• Very occasionally, larger amounts of other items and larger items (like furniture) are offered via email. For example, a coworker once inherited a relative's large collection of SF paperbacks, didn't want them personally, and thought others would be interested because we talked about SF a lot. This was a "you're welcome to come to my house, look through boxes, and take away anything you like" offer. How acceptable this is correlates with how likely those specific coworkers are to be interested in the item.

Only offer to pass along things that you can reasonably believe your coworkers would find valuable. Otherwise, there are charities that will be happy to accept donations of usable items and put them to use helping other people.