Some brokers are now beginning to quote the other major currencies to five decimal places. Logically this should mean that one pip would be 0.00001 currency units, but the potential there for bafflement is big, if a pip would be worth 10 times as much with some brokers than with others. So it seems likely that the pip will stay at 0.0001 units for most currencies.
Most traders record their profit and loss in foreign exchange trading pips as well as in money. This enables straightforward comparison of one trade with another so that you can guage a system. It also means that traders can debate their results in a foreign exchange forum without revealing the size of their account or their profits in dollars and cents.