The key word here is useful – spammy comments on social networking and blog sites will be deleted (or simply not approved). If you post the same comment on every third party site then the search engines will spot your game immediately. If you make comments on websites that are useful to the other users of the site then you’re less likely to cause offence.
If you’re particularly knowledgeable you may even start to be seen as a useful member of the community and encouraged to get more involved. Don’t forget that these comments you’re leaving also have the potential to bring you organic traffic -people that click on the links you leave – so be useful and be interesting! Leaving useless comments can also reflect negatively on your brand, so be careful.
How to figure out where to post comments
I use the free Google Alerts service to find out where in the blogosphere people are talking about the keywords that I am targeting. These alert emails will often cover ground they have previously churned up, so it’s important to think carefully before charging off to leave your mark.
But is leaving comments for SEO advancement evil or unethical?
No I don’t think it is – I thought long and hard about whether to make this post and share this technique but I decided that as it requires a lot of thought and (like all good SEO) isn’t a quick fix then it isn’t unethical. If you were to use software or a script to leave comments then it would most definitely be evil SEO, and you would probably be punished by being dropped from rankings, and quite rightly so!
It’s my opinion that contributing to the usefulness of the web is at the very heart of good SEO practice, and it’s an opinion that is re-enforced by the results it yields.
There is a HTML attribute called ‘nofollow’ that impacts on this plan, I’ve written a blog post about it here - http://lawsie.blogspot.com/2009/11/surely-google-spider-ignores-nofollow-3.html