|Holding the line between popular and generic|
(The Thin Red Line 1854 Richard Simkin)
Trademarks, unlike copyrights and patents, are granted primarily as a means for consumer protection. Valid and enforceable trademarks allow consumers to be more confident in the source of that product. If a trademark fails to identify the source, then it fails its primary function, and should not continue to receive trademark status.
This is the rationale for the revocation of trademarks that become "generic". A good example is the previously trademarked term "thermos". A thermos was once a product of a single company, but the term became generic as people referred to all similar goods (regardless of manufacturer) as thermoses. Once generic, the term no longer qualified for trademark protection.
A common way for trademarks to become generic is when they are commonly used as verbs. Xerox (the company) fought hard to stop people from using "xerox" as a verb (e.g., "I'm going to xerox this document"). When used as a verb, it's easy to see that a trademark can be used generically. One can imagine "xeroxing" a document on a Ricoh photocopier, for example. This situation is deadly to a trademark.
In the case of MPesa, it is extremely (and should be worryingly, at least to Safaricom) common for people to use "MPesa" as a verb, as exemplified above. This Leo has even heard people say they will MPesa some money over Airtel, a competitor service. Such use of the trademark is improper and diminishes the ability of the trademark to indicate a product source.
The proper use of a trademark is as an adjective - e.g., "I'm going to send you money using the MPesa mobile money system." Quite a mouthful, but it clearly indicates the source of the product.
Brands that pioneer a product/service such as MPesa must always walk the thin line between being popular and becoming generic.