They are viable, but growth is significantly hindered by GOOGLE. When you install a search engine extension, that is explicitly labeled as such, Google will sti

They are viable, but growth is significantly hindered by GOOGLE. When you install a search engine extension, that is explicitly labeled as such, Google will still "warn" users that an extention has "hijacked" their default search provider, and recommend to revert back. This is obviously anti-conpetitive but governments are too slow to react. Furthermore, extensions are at the mercy of extension stores' obscure policies, and are often dropped on a whim by "reviewers". With that said, tens of millions of users is hardly "unviable". There are several profitable search engines.