Rearden Commerce, the Silicon Valley company wanting to be your personal concierge for things like booking travel or restaurants, says it’s growing quickly.

First, it has acquired ExpenseWire, a company that will help it add business expense management to its offering. Under the terms, Wooster, Ohio-based ExpenseWire, will continue to serve its other customers.

Second, the Foster City, Calif.-based Rearden Commerce said it has added more than 800 corporate customers and 500,000 contracted individual users in the first six months of the year. In the last 18 months, Rearden Commerce says it has added more than 2,000 customers and 1.5 million contracted users.

Rearden’s online service can be used on your mobile phone too, as we first reported a couple of months ago.

And now the company has introduced an international component to its mobile service. Offered through Voyport, a provider of international mobile roaming, the new service lets companies using Rearden Commerce’s mobile version reduce roaming charges by up to 75 percent. U.S. carriers charge mobile roaming fees of up to $4.99/minute from some countries.