Clever wordplay ("zip" + "city") with positive connotations that could suit many uses. For instance, a company that manufactures and designs zips.
Also, a commuter app, that helps people move around a city quickly. It could suit a company that created a travel app (i.e. something helping people understand and navigate a city).
The word "zipacity" contains eight characters and four syllables. Leading companies using four syllable names include Coca-Cola, ESPN and Unilever.
This domain was first registered in April 2013. Older domains have an advantage when ranking in search engines.