Firstly, the obstacle of Web 2.0 is that the service is limited to a specific country (region), which we call geographic limits. Some of the countries in Southeast Asia and South Africa do not have stably settled down fitness apps yet. Secondly, most of the Web 2.0 apps have currency transaction limits so that the earned rewards from the APP are in the form of that country's currency. In conclusion, Web 2.0 created in certain countries has limited use and is hard to expand the service to other countries or the world.
Thirdly, in terms of Web 3.0 M2E services, 3 main limitations exist; profitability, playability, and accessibility. Lots of current M2E services do not have business models that benefit the company and its users simultaneously. The existing M2E does not have a firm business model in which users and projects can coexist so the profitability seems vague in the long term. Fourthly, M2E services are on the same page as play-to-earn (hereinafter, P2E) services but lack playability. There is less feeling of 'playing' the service with one's own profit within the app, and other M2E services are designed difficult to see at a glance how their steps return to profit. Lastly, accessibility is also important for M2E services to let people join the services at any time although the services started way before the new users sign-up. Since recent M2E services are designed in such a way that only the existing initial users make a profit by holding NFTs, it is difficult for new users to start and for the project to maintain the number of users as time goes by.