I use tabs, but have them organized into a vertical tree. This allows many more to be visible at a time. Since they are in a sidebar, you interface with them like bookmarks, but they don't spawn a new tab when clicked. Because they are organized into a tree structure, its easy to recall the purpose of each.

For example, a search engine tab might lead to a stackoverflow tab which might lead to a few documentation tabs. As long as you remember what the documentarion is for, you can tell what the SO thread is about, and what is was you searched.