For those not totally aware of what Squidoo is, I don't intend to go into the ethos of the site right here, other than to state that it can be used as a promotional tool as well as a being a virtual website. Your lens can also be given a Google PageRank. You can use your Squidoo lens in place of a minisite in order to promote yourself and your product, and improve your search engine listing. You can use it as a showcase for your products, your blogs or even your websites, and draw traffic to it and hence to those other online ventures you are involved in.
In order to use Squidoo as a promotional tool for your main website you have to know a lot about the topic of your site. It is not a tool to use to sell an affiliate product, for example, unless you are an authority on that product. However, if you have written a book on a certain aspect of SEO, and want to advertise it, then Squidoo is ideal for that. The reason is that you can give in order to earn. Hence, Squidoo is great for me, because I can provide visitors to my lens with useful information on SEO, while at the same time advertising my SEO site that offers my product. I then get visitors and a link from Squidoo, both of which are great for my search engine rank, and also listing position.
It might be possible just to advertise the product directly, but I prefer to provide information. That allows your visitors to become confident that know what you are talking about, and are not just a 'fly by night' that is trying to sell a product that you know nothing about. The objective of Squidoo is to provide useful information on topics to others interested in that topic. If they go to Squidoo and click on a category, they should be able to find all the info they are looking for.
They don't want outright adverts, but if they find that you are providing good information, then they might want to visit your website. You give them the link to do so, and then they get more information. Part of that might be the offer to purchase your product that will possibly solve their problem. However, neither you nor they know that it will, so you provide them with a guarantee that if it doesn't work for them, they get their money back. You have used Squidoo to persuade them that you know what you are talking about, that led them to your site and more information, and then to your product. They buy it, try it, and if it works fine. If not, they get refunded. In my book that is the proper way to conduct business, and you can use Squidoo to help you with that.
You can also optimize your lens for maximum search engine listing position, since your Squidoo lens should be based upon a single keyword or keyphrase to enable you to get a good listing. You can SEO a lens just as you can do a web page, and with the same effect. Free organic traffic from your listing position.