I was just wondering if the programming language or database you use has any effect on selling your site to another company? I mean is it easier to sell PHP site than other language? How about database type? If I was using Redis instead of MySQL, would that make any difference?
I think its a consideration, but a secondary one. If the site is valuable enough to the customer, then they will buy it regardless of the technology used. That said, unless you plan on supporting that site into perpetuity, it is probably a good idea to use a more commonly used web programming language, like PHP, Python, or Ruby. Otherwise, it will be more difficult for the purchasing company to find programmers to maintain that site after you're gone.
I guess it would depend on who you're selling it to. Clients, especially ones with little technical expertise, can be prone to trendy buzz words as everyone else. I once had a client who wanted an ERP for his smallish company and wanted the back end to be Oracle, because a little bird told him that Oracle was "the best". Fortunately, one look at the licensing fees shut him up :D
Another, more legitimate, factor is if the client wants to staff the website from his own team. Having a website that runs the same technology that his team is familiar with would be a plus in his view. That being said, if the web site's perceived value trumps whatever additional cost the client would need to invest, then chances are good that the underlying technology wouldn't matter so much.