If you can't get enough of the big gray boxes that line our nation's highways, then you should be happy with Wal-Mart's (NYSE:WMT) latest plans. Yesterday's release detailed management plans for expansion that, to judge by the headlines, will give us 8% more square footage to love and/or loathe, in the form of traditional stores, Supercenters, Sam's Clubs, Neighborhood Markets, and international branches.

It will certainly be enough to stay ahead of competitors in the space, such as Target (NYSE:TGT), Costco (NASDAQ:COST), Dollar General (NYSE:DG), Family Dollar (NYSE:FDO), and just about everybody else. But while it sounds like a lot, the circa-185 tally for new U.S. stores is actually smaller than what was planned in last year's nearly identical release. A more notable difference is that fiscal 2005 (this year) called for 100 new international locations, but the 2005 goal is 35% higher.

It's not hard to figure out why. Even without the $1.5 billion boost from foreign exchange gains, Wal-Mart's international revenue growth is outpacing domestic sales by a hefty margin. For the first half of this year, international revenues constituted more than 19% of Wal-Mart's total sales. That performance helped perk up margins earlier this year.

But a bigger foreign presence isn't necessarily the final antidote for sagging comps back at home. Operating margins were 5% overseas so far this year. Sure, that's a lot better than the 3.4% at Sam's Club, but it's not nearly as juicy as the 7.5% enjoyed by domestic Wal-Mart. Moreover, those pesky foreigners aren't always so excited to have America's gorilla retailer, or its local surrogate, roll over the indigenous merchants.

Time will tell whether this strategy pays off. Until then, investors need to keep an eye on the firm's same-store sales. If growth is coming mainly via expansion, the shares should be priced accordingly.

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Seth Jayson has no positions in any company mentioned. View his stock holdings and Fool profile here. Fool rules are here.