Newsletters are a big thing in many websites nowadays. Websites ask people to subscribe to their free newsletters and keep sending out information every week or sometimes more frequently depending on the strategy that they follow. Whether this was a good idea in the first place or not, it really is a waste of time nowadays. Most email applications offer anti spam filters and most newsletters only end up in the junk mail folders.
You may think that even if a very small percentage of people to whom you send out the newsletters read them it is good because the cost of sending them out is low, you are only shooting yourself in the foot here. You will only be classifying your website as another pusher who is trying to push something, in everyone's minds and will therefore lose out on your brand image.
Give them the option
A better idea is to give the option to people to subscribe to an RSS feed. This gives them the option to either choose to subscribe or not which means that only genuinely interested people will. It will also give you a much more accurate idea of how popular your site is because most of those who subscribe will actually read what you have to say.
One of the best ways of generating interest in these posts is to give insider information. Don't just write rehashed information that is easily found in other places online. If you are recommending a particular software for a specific purpose give honest impressions that are not found elsewhere. You may think that this is too much to give away freely, but look at it this way. Open Source is catching on like blazes now, and there is a free alternative to almost everything, including Operating Systems. If you want to charge for your opinions as well as for the product that you sell, you will find that someone else is only charging for the product and is offering their opinions freely resulting in a movement away from your site.