How we view competitions between the converging Internet social platforms: Does higher user number mean the final victory?

We propose a special opinion model on Internet users' social platform selections where users only view those converging platforms as tools to maintain their communications with all of their friends or partners and one may use more than one platform at the same time. We construct the time evolution differential equations, seek the fixed points, and study their attractability and repellency by analyzing those equations. Then, we verify the analytical results and observe their accuracy by numerical simulation. The conclusion shows that in any practical system described by our model, one platform will completely eliminate its competitor sooner or later, and when the average degree of the interaction network is relatively low, the laggard may have more chance to turn the tide, but when that average degree is high, that chance is extremely limited.