Vexed in the city: The tech invasion of San Francisco (pictures)

Mayor Ed Lee (left) exults, flanked by Riverbed  Technology CEO Jerry Kennelly at the ribbon-cutting ceremony celebrating the opening of a new corporate headquarters in downtown San Francisco. In the last couple of years, many technology companies large and small have chosen to put their headquarters -- or open branch offices -- in San Francisco.

The tech industry is raising its physical profile in San Francisco. For instance, Salesforce.com, already San Francisco's biggest tech employer with 14,200 workers, will lease more than half of a 61-floor high skyscraper bearing the company's name. City officials expect the 1.4 million square foot tower to fill up by the time it's in move-in condition upon completion in 2017.

For years, Mission Street was a working class community with a large Latino population. Attracted by the neighborhood's great weather and original architecture, newcomers working for tech companies are moving into Mission. Their arrival has not gone unnoticed as it has coincided with rising rents and increasing evictions.

Across the street from CNET's downtown San Francisco offices, LinkedIn will be moving into a 26 story skyscraper -- yet one more vivid instance how the tech industry is physically transforming the city's skyline.

Fremont Mayor Bill Harrison wants to compete with San Francisco and other Bay Area locales for tech jobs.

Here, Harrison stands in the under construction Warm Springs BART subway station, which is set to open in 2015 adjacent to Tesla's auto assembly facility.

One of the centerpieces of Fremont, CA.'s plans to lure tech firms is a the new Warm Springs BART station that's now under construction.

 Venture capitalist Tom Perkins ignited controversy earlier in the year when he compared criticism of the wealthy to the Nazi persecution of the Jews.

The perks at Silicon Valley tech companies have become a major pull for potential employees, and these bonuses are part of an ever-expanding suite of compensation.

Here, dry cleaning just back from the laundry hangs at Facebook, waiting for pickup.

This stunningly designed conference room at Airbnb mimicks the style of the film
"Dr. Strangelove."

Salesforce's 6 foot, 5 inch CEO Marc Benioff has personally donated more than $200 million to Bay Area hospitals. Meanwhile, a philanthropic program his company started since 1999 has donated more than $68 million with Salesforce employees volunteering some 680,000 hours of their time.

Facebook CEO Mark Zuckerberg is one of the tech CEOs calling on Congress to fix what has been described as a broken immigration system. Meanwhile, the controversy over H-1B visas for foreigners shows little sign of fading -- especially when many US-born engineers can't find jobs.

Reid Hoffman, LinkedIn co-founder and nowadays a partner at venture capital firm Greylock Partners pauses as he speaks to undocumented hack-a-thon participants at a FWD.us event at LinkedIn in Mountain View, Calif.

FWD.us is pushing to engage the tech community to advocate for immigration policies.

Ron Conway, one of the most connected people in tech and political circles: "The tech community understands that it is relatively new to San Francisco and is committed to working with community leaders to work through these issues."

Along a once-grimy stretch of Market Street, startups are moving in and formerly vacant offices are buzzing with new activity, such as at this Amazon Pop-Up Loft.

Startups and other tech-centric business are moving into long neglected areas near Francisco's central artery, Market Street.

For better or for worse, for richer or poorer, San Francisco is changing, again. In ways that seem to highlight the divide between rich and poor, between the haves and the have nots, the tech and the tech-nots, and the build and the build-nots, this is the new, NEW San Francisco.

Airbnb, whose offices are pictured here, says 82 percent of hosts rent only places where they live. But given  San Francisco's low vacancy rate of 2.9 percent, housing advocates worry that the popularity of the startup service is contributing to a reduction in the rental stock in an already tight housing market.