Web 2.0 is the term given to describe a second generation of the World Wide Web that is focused on the ability for people to collaborate and share information online. Web 2.0 basically refers to the transition from static HTML Web pages to a more dynamic Web that is more organized and is based on serving Web applications to users.
Using nofollw was am advanced SEO link sculpting activity that grew in popularity in 2008 and the start of 2009 but it was never something that we advocated. The idea was to add a "nofollow" command to internal links that you did not want Google to take into account when interpreting your website. Nofollow is a syntax that Google and other search engines collectively came up with as a way for a website owner to say to a search engine that they do not have any opinion on the relevancy of the page they are linking too.
There are a lot of seo companies who can help you in getting top ranks in search engine result pages. We are also doing the same job for our clients in India, UK, Canada, Singapore etc. For contacting us you can click on the link given in my signature.