Create/Manage PHP/MYSQL website with millions of users

As an estimate, the website will have millions of users in the next few months, with an approximation of 10,000 active users at once posting comments and interacting with the site (somewhat simple searches / mysql queries /comments). Site features will include: Items with tagging Favortes Most popular Lots of photos Comments Member profiles Subscribe buttons, showing subscribed items on users homepage (the most complex feature, how would we implement this? ) Mostly, we have quite simple features, but the key needs to be keeping costs down as the site will not be generating any revenue for me. I'll choose the best candidate based on the private message you send me, which should include a development plan with an approximate cost, monthly cost for maintenance. Why are you better and more reliable than other candidates? What experience have you got in this area? How sure are you that you can manage a site with around 50-100,000 daily active users? I'm a passionate web developer (with basic knowledge - but still allowing me to create almost anyway website - in a sort of messy way with no structure). I have no experience when it comes to scaling and keeping costs to a minimum by caching everything as well as possible, managing the servers etc. So ideally I would like to have someone else create and manage that side on an on going basis. If you have a lot of experience in this area I would like to hear from you. Freelancer is full of bad quality programers and companies that have been setup overnight that send copy-paste messages to everyone. To clarify, if I get a copy/paste private message from you, you WILL be ignored. You have to put some effort into explaining how everything will be done, in order to get a reply from me. If you are highly skilled, you will be rewarded in the future when the site takes off. The website will be thoroughly tested before launch, I've been a member on freelancing sites for over 5 years, if you can demonstrate your skill in the first message you send me, you will have a VERY high chance of working for me. Happy to work with someone on this on a part-time basis for the future development of features, if you are good at what you do we will no doubt have a great working relationship together as more sites like this will be created on an on-going basis....