Here are five things to consider: popularity, control over copyright, revenue sharing, format, and RSS feed availability.

The upside: YouTube is incredibly popular. Their massive user-base is constantly searching and perusing the YouTube library. They have an exceedingly simple interface for publishing video.

The downside: When you upload videos, you agree to allow YouTube to commercially exploit your work in any manner they see fit. Furthermore, they aren't obligated to share any of the profits they make off your work. Your videos are only accessible in the Flash format (no iPod video, etc). You must often wait for 1-3 days for an uploaded video to become playable. Max video length of 10 minutes.

The upside: blip.tv leaves the author in full control of their copyright (aside from making the video available on the blip.tv website). They have an opt-in advertising service and share revenue generated by this system. You have partial control over video format. blip.tv offers a great video subscription interface. Videos are generally playable immediately after upload.

The downside: blip.tv is not as popular as YouTube; as a result, their library isn't searched quite as often.

The upside: EngageMedia is a non-profit with a mission to provide media tools to activists, campaigners, communities and citizen journalists. Any video format you upload will be available to your viewers. The site strongly encourages Creative Commons licenses, which means that many of the videos on the site can be freely redistributed and/or remixed.

The downside: EngageMedia has even fewer individuals searching their database (however, search is not the only way to be found).

In our opinion, YouTube, blip.tv and EngageMedia are three archetypical examples of video sharing sites: one with a massive user-base, one which gives the author a great deal of control over her or his videos, and one with a non-profit social mission.

They are great sites, but they are by no means the only option — we encourage you to look at some alternative services.