It's their 12th birthday, and next weekend the LostCousins site will be completely free - it's a great opportunity to contact the cousins you've already found, and to find new cousins. The offer runs from Friday 29th April to Monday 2nd May.
LostCousins identifies members who share the same ancestors by comparing the information each member has entered on their My Ancestors page. After all, if you and another member have both entered the same relative, the two of you must also be related to each other!
Once you've entered your information the rest is automatic - all you need to do is click the Search button whenever you want to search for new cousins!
What makes all this possible? The fact that every LostCousins member is taking information from the same online censuses.
Where can you find the census data? Most of the censuses have been selected because they are available free online. Usually only the transcription is free, not the images of the handwritten census schedules - but where that's the case all the information you need will be available as part of the transcription.
There is a very good help page on the site.