It's nice to encourage the creation of fun, walkable urban places, but it's not always fun to walk around when it's really hot or really cold or raining outside. There's one thing the mall will always have over downtown, and that's a climate-controlled environment. But urban places can strike a nice compromise by creating arcades, or covered sidewalks.
Most strip shopping centers have arcades, like this one at Plaza del Mercado in Layhill. This is nice: you can walk here and be sheltered from the sun, rain or snow. But you can't really occupy this space. There are no benches or tables for sitting or eating, and like most shopping centers, loitering is generally discouraged.
This is the arcade under the Twin Towers Apartments at Georgia Avenue and Fidler Lane in downtown Silver Spring. It's a pretty miserable space, barely wide enough to walk through and very dark. Note that it's also elevated above the sidewalk, meaning that passersby can't really look in any of the shop windows (are there even still shops here anymore?)
Traditionally, an arcade would cover the entire sidewalk, not just a portion of it, as it's meant to be a public space. Why doesn't it here? Perhaps zoning, or the Department of Public Works - fearful that the building would prevent them from widening Georgia Avenue in the future (God forbid) prevented any portion of the building from extending over the property line.
This arcade is along East Montgomery Avenue in Rockville. The building behind it houses several shops and restaurants and the Regal 16 Cinemas and, as a result, the space has lots of life and activity. It also covers the entire sidewalk, creating a sort of long, outdoor room. There's space for tables and chairs, for benches, with ample room left over for walking and window-shopping.
Long before Rockville Town Square opened, this arcade became a major hangout for local kids and remains so today. The enclosure not only provides shelter from the elements, but it creates a nice, intimate space for interaction. We'd do well to create more arcades like it.