Trackbacks are typically used by blogs and commenting bloggers can notify another blog with a “trackback ping”. The blog receiving the trackback ping will then display short summaries of and links to all the commenting entries below the original blog entry. This is a great way to let others know you’ve commented about something they wrote and allows you to network with other bloggers. This also means…
Lots of potential backlinks. Search engine optimizers love them. Search engines hate it when it is consciously used to manipulate the search results.
PR Web now allows trackbacks in their press releases. These trackbacks don’t carry the “no follow” tag that Matt Cutts encourages.
The spam cops complain that this will just add more spam to the search results. The reality is: Press releases can, by themselves be spammy content designed to inflate a site’s link popularity. The news media has been bombarded with press releases for years now. Many turn out to be junk and never get published while some others slip through.
As long as there is something to gain from being in the top results, search engines will have to contend with spam. There are savvy marketers who use press releases as one of their primary methods of generating higher link popularity. With some research and creativity, anyone can churn out a press release on a regular basis to promote their site.