Regulation and taxation can also be an issue; generally speaking, they vary greatly depending on market and do not support a highly innovative business environment. Faced with slowing revenue growth from voice and text services, carriers are seeking new sources of income through value-added services, or VAS. Over-the-top (OTT) providers, such as Skype, WhatsApp, and Line currently own this competitive environment. Carriers are responding now with a GSMA supported platform called RCS OTT messenger platforms (Rich Communications Services). This platform allows carriers to offer similar services as OTT messaging providers (e.g., image or file sharing and VoIP), but without having to tap into the data allowance of the consumer. The success of this platform is likely going to succeed or fail with the quality of the user experience. 42