"What am i using it for?" All depends on what scale your project will be within :
Please note the suggested platforms are limited to those within my knowledge, there are bound to be a multitude of other options, these are the common and well known platforms suggested. Also the platforms suggested per scale are based on affordability and availability. hits are based off database not pages.
Ultra Small Scale : very low traffic(under a couple hundred hits a day), limited data storage, low connection allowances, typically in home, small office, or development environments. Suitable data sources would include : MsAccess, Text, and MySQL
Small Scale : low traffic (couple hundred hits a day plus), limited data storage, fairly low connection allowances, typically in office, team development environments, intranet, schools, and small business. Suitable data sources would include : MSAccess, MySQL, PeachTree, and FoxPro.
Medium Scale : medium traffic (hundreds into low thousands a day), decent storage, still fairly low connection allowances, typically small business web stores, low level forums, etc. Suitable data sources would include : FoxPro, PeachTree, MSAccess(only if data connections are kept to a minimum), FoxPro, Oracle, MySQL, and Paradox.
Large Scale : heavy traffic(low thousands plus a day), large amounts of data storage, large connection allowances, Typically commercial web stores, high volume forums, personal web sites, bug trackers, etc. Suitable data sources would include : MS SQL, Oracle, and Paradox.I'm unsure if MySQL's capabilities extend this far