OthersOnline is a Firefox and IE add-on that allows you to meet people with the same interests as yours. The way it works is that it keeps a track of what you visit online, the frequency you visit a page, and your search engine searches.
With all this information it creates a profile that should be quite accurate on what you are interested in, so that you can see who is online in that moment and have a chat, sharing opinions or asking questions with the guarantee that the person you are contacting is acknowledged about the subjects you are interested in.
Although your privacy might be at risk, you can sign in and sign out at any moment and that leaves you the freedom to decide what you want the application to track and what no.
There is also a filter to block 'adulty content, which is set as default in the user option menu.
The program is easy to use, just surf normally, and then click the 'global' menu to see all the relevant profiles of other users.
You can then visit their blog, email them or see what you have in common. In the user options you can set to display just users who live near you, by specifying the miles of distance from you.
If you are willing to compromise a bit on your privacy, you can meet people with your own interests online and why not, offline.