While I like Melissa, as others have mentioned there are international as well as phonetic issues with it. Many languages don't have 'L' sounds--which could lead to user issues. Also using a common proper name will have some issues as well... One of which you've already discovered domain names, the other may be the Melissa's of the world not being to pleased with their name being associated with a digital servant.. While their is a shortage of great available domains. For longevity, you may want to consider looking at your entire product experience and branding and align them into a more coherent system that can evolve as your business shifts and changes.