When you make backlinks from web 2.0 sites does the article have to be 500 words? is it still effective if I just wrote 300 words instead?
300 words article is not sufficient. How can you cover a topic in 300 words when you are creating content for web 2.0. Article should be descriptive 500 -1000 words and after createing web 2.0, generate some traffic on that. Such backlinks really helpful your site and Google will consider it genuine/natural link.
Squidoo is a great place that 300 words would work for. aside from that onlypmme is right they do need to be a bit longer... sorry