I know of some bloggers who say that Entrecard is useful only when you can make 300 drops each day. While that might be partly true, there are other ways that you can benefit from being part of this blogging community.
How about this? Let's say you've just written a very informative and wonderful post that you think a lot of people would have a good time reading it. How can you, sort of, spread the word?
After publishing your post, start dropping your EC especially to those bloggers whom you think would like your post. About 100 drops would be enough but if you have the time, by all means do 300 drops.
This is like tapping these bloggers and whispering to them, "Hey, why not visit my blog today? I've got something really nice posted there."