Internet-related businesses are driving an IPO market resurgence in 2011, while also raising concerns about the similarities to the dot-com bubble from a decade ago. Zillow debuted July 20 and tripled in value in early trading before settling for a nearly 80% first-day gain. Investors rewarded the company despite numbers in its IPO registration indicating that Zillow, operator of a real estate Web site, has never made a profit. The deal is representative of the strength of this year’s IPO market, a fact that is also backed up by the half-year IPO filing numbers.

With 93 completed offerings in the first six months of 2011, the IPO market is comfortably ahead of last year’s pace of 70 IPOs through the first half of the year. Where this year’s market really shines is in the amount of money that new issuers have been able to raise. Through the end of June, companies have generated more than $26 billion in IPO proceeds, compared to $9.8 billion in the same period last year. 2011’s six-month total exceeds the total for all of 2009 ($24.8 billion) and nearly matches 2008’s yearly total of $28.14 billion.

At its current pace, the 2011 market may approach the impressive aggregate proceeds reached in the 2007 IPO market. In that year, 282 IPOs generated $60.59 billion in proceeds, the highest annual total of any year since 2000. The six-month total in 2007 was $29.28 billion, very close to what this year’s market has achieved so far.

This year the market has already seen five IPOs top $1 billion in proceeds. Only two offerings surpassed the $1 billion mark in all of 2010, although one was General Motors’ $15.77 billion mega-deal. 2011’s largest IPO to date is HCA Holdings’ $3.78 billion offering on March 9th. The other issuers that have completed IPOs with aggregate proceeds over $1 billion this year are Kinder Morgan ($2.86 billion), Nielsen Holdings ($1.64 billion), Yandex ($1.3 billion) and Arcos Dorados Holdings ($1.25 billion).

Of 2011’s 93 IPOs through the end of June, 28 were completed by non-U.S. companies, which is close to last year’s pace when 57 issuers incorporated outside the U.S. went public in the U.S. Chinese companies account for more than half (15 of 28) of this year’s deals by foreign issuers. One of the non-U.S. companies was headquartered in France, which is the first time a French company has gone public in the U.S. since 2000. Sequans Communications, which is based in Paris, raised $77 million in its April 14th offering.

May was the busiest month for new issues so far this year with 24 offerings. April was second with 20 deals. May also boasts the top newsmaking IPO of the year so far, which is LinkedIn’s May 18th market debut. The company’s shares priced far above the stated range at $45, but intense investor interest still drove the shares to a 109% gain by the close of first-day trading. The offering was one of several successful debuts by Internet-related issuers, which have made a comeback in 2011. Also making a comeback this year are Blank Checks companies (SIC 6770). The industry has tallied 12 IPOs so far, twice as many as the next closest industry groups.

In the first half of the year, 100 law firms participated in some form of IPO representation, as either issuer’s or underwriters’ counsel. That is 18 more firms than in the comparable period last year. Latham & Watkins leads the rankings by number of IPOs with 18 representations, and Davis Polk & Wardwell is second with 16 representations.

Latham shared the top spot in the 2010 year-end rankings with Simpson Thacher & Bartlett at 30 assignments apiece. Through half of 2011, Simpson Thacher holds fifth place with 10 representations. Just ahead of Simpson Thacher are Wilson, Sonsini, Goodrich & Rosati with 12 representations and Skadden, Arps, Slate, Meagher & Flom with 11 IPO assignments.

Ranked by total offering amount, Simpson Thacher holds the top spot, narrowly outdistancing Davis Polk $6.75 billion to $6.23 billion. Simpson Thacher served as issuer’s counsel to HCA Holdings and Nielsen Holdings, both of which raised more than $1 billion in proceeds through their IPOs. The firm’s 10 representations are split evenly between issuer’s counsel and underwriter’s counsel assignments.

Davis Polk has served as underwriter’s counsel on 11 IPOs so far this year, and has been issuer’s counsel five times. Its second place ranking by aggregate proceeds reflects the firm’s work on two deals that topped the $1 billion threshold. Davis Polk served as underwriter’s counsel to Yandex, and was issuer’s counsel to Arcos Dorados Holdings.

Although the order has shuffled, the top 10 underwriters through the first half of 2011 are the same 10 managers that ended 2010 atop the rankings. There has been no movement at the top of the list where Morgan Stanley, which led the 2010 rankings, is in front again at the halfway point of 2011. Morgan Stanley’s 27 IPOs place it comfortably ahead of Deutsche Bank’s 22 offerings. JPMorgan, Citi and Bank of America each led 19 deals in the first six months of the year, and complete the top five spots in the list of busiest IPO underwriters.

Eight of the top 10 lead managers have surpassed the $10 billion mark in aggregate proceeds, a testament to the strength of the market in the first six months of 2011. Through the first half of 2010, no underwriter even approached the $10 billion level. Morgan Stanley’s industry-leading total at June 30, 2010 was $4.46 billion. Morgan Stanley is the six-month leader again in 2011 in the ranking of top lead managers by aggregate proceeds. Its $14.3 billion in total proceeds is nearly $1.6 billion ahead of the $12.7 billion raised in Goldman Sachs’ first-half deals.