I definitely agree that the actual conversion rate of traffic to paid user is low -- we're hoping to get that number up to around 1% some day. I wouldn't say it's misleading though since we did actually triple the visit to paid conversion rate.
Well...maybe. What are the numbers? If you converted 4 people on 1000, the 95% confidence interval runs from 0.2% to 1%. The difference between 1 conversion in 1000 and 4 in 1000 isn't significant.
But if you converted 40 on 10,000 (vs. 10/10,000), that is significant. So if you've got big numbers to back up your tiny conversion rate, you should just write that into the blog post to silence these sorts of critiques. You don't even need to be specific -- saying that your N is of a certain order of magnitude would be enough to make most reasonable people take you seriously.