First off...Happy Halloween! We've come to the last day of Family History Month.
The last thing I will talk about for social networking is Online Family Trees. I have covered a couple of the big sites that host online family trees earlier this month. There are others I haven't mentioned as well. In those I mostly focused on how to contact individual users and connect on the site. Not all online family trees are visible to the public, some people choose to keep theirs private.
There are also personal family tree websites. Some are hosted through other big sites (e.g. Famberry or Family Pursuit...), some are self-hosted websites. While family trees through those sites are often restricted so just family members can view them, self-hosted sites are usually publicly available. They usually have a family tree, sources for their information, and stories and photos. There is no standard template, so finding information on a site may be difficult. One nice thing about stand alone websites is that they are searchable. You should be able to find them with any search engine (like Google).
As for family trees hosted on the big sites (Ancestry, MyHeritage, FindMyPast...), you can search the site for names and information. Doing this can lead you to more sources and filling in branches of your own tree. If the tree want to see is private, you can request access to it, or send a message to the owner and ask if they have certain information you want.
I hope you search for family trees online, and search within the big sites for other trees that match up with yours.
Happy Family History Month!