Regularly updating your website, lets other websites know you have fresh content and are paying attention to your website, thereby making your website more likely to have quality, relevant information.

However, the other websites need to know you updated your website.

The way you do that, is after making changes to your website, go to Pingomatic.com and fill in the information on the form. This is a free service, because they like to collect the data.

See How Blog Pinging Works