Pick a random blog and odds are that blog doesn't provide a facility to subscribe to its RSS feed via email. I find that quite strange. Why would you not provide an R-mail widget on your blog? Some of the blogs I host have a significant numbers of their subscribers from R-mail and one has more than 50% of their subscribers (46 of 79) from email services. In fact, two blogs (that I don't host) have over 100 R-mail subscribers. Honestly, if you don't provide your readers with an RSS-2-email solution, then you are not really trying to maximize your subscribers. The best part is that adding an R-mail widget to your blog is trivial.
Simply place the following HTML code on your blog. You can see a sample floating on the right.
<form action='http://www.r-mail.org/' method='post'><div> <script type="text/javascript"> var rmail_rss = "http://feeds.feedburner.com/Rmail"; document.write("<input type='hidden' name='rss' value='" + rmail_rss + "' />"); </script> Email:<input type='text' name='mailto' value='' /></div> <div><input type='submit' value='Subscribe' /></div> <div style='font-size:xx-small;'> <a href='http://www.r-mail.org/'>R-mail powered</a></div></form>
And don't forget to replace the RSS feed URL in the first line of the <script>, third line of the HTML with your own RSS feed URL. Also, feel free to modify the HTML, add styles, etc.