The Citigroup (C) analyst spoke with PubMatic and the Rubicon Project, two “optimization” firms that help publishers manage inventory they hand over to ad networks. And both say they’re seeing continued upticks in sales and demand.

Pubmatic, for instance, says pricing has increased every month this year, and Rubicon says that they’re seeing demand from–believe it or not–travel and auto advertisers. Just as encouraging, buyers are actually making “longer-term” plans, which was unheard of in the darkest days of 2008 and 2009.

Both firms also reiterate the conventional wisdom that we’ve been hearing for the past 12 months: The money that is being spent is increasingly going to “performance-based” ads, which are paid for only when someone interacts with them. That’s another data point in favor of Google (GOOG), whose core product is performance-based.

Again: Things were so lousy a year ago and through the spring of 2009 that it’s prudent to take these kinds of data in stride.

And if you really want to be half-empty about it, you can note that the inventory Rubicon and Pubmatic sell is the cheapest real estate publishers have to offer. Which means it’s hard to say how various sites’ high-end real estate–the stuff they sell themselves–is doing.

We’ll get a better sense of that in about a month or so, during Q3 earnings season, when we get color from Web publishers like Time Warner’s (TWX) AOL and the New York Times (NYT).

But, as I said, this is supposed to be an optimistic post.

Anmuth says his research shows an increase in pricing for Google’s search ads over the past few months, particularly in the battered retail and auto sectors. His note comes a couple days after Citigroup’s Mark Mahaney raised his Google estimates, citing a dramatic improvement from mid-August to mid-September.

Other Google bulls: Investors, who have been pushing up the company’s shares since March (they’re now hovering near the $500 mark again), and CEO Eric Schmidt, who declared this week that “it’s clear that the worst is behind us.”

The tempered enthusiasm isn’t limited to Google’s chances, by the way. Mahaney also had good things to say about Yahoo’s (YHOO) chances as the economy recovers. While Yahoo is handing over its search business to Microsoft (MSFT), Carol Bartz and crew still dominate the display ad business, and that should be picking up as well, he said.

It is worth noting that Yahoo executives themselves were more cautious this week when asked to describe market trends: At an Advertising Week press conference, Bartz brought out her “still bumping along the bottom” line, while EVP Hilary Schneider said ad sales had stabilized but that she “wouldn’t go so far as to say as we’re seeing a full recovery.”

Car companies cut their ad spending by 10 percent, to $6.1 billion, through the first half of the year, according to Nielsen’s ad tracking service. That confirms anecdotal evidence media companies have been offering up throughout the year, and it means that the numbers for the second half of the year–when the economy really collapsed–are going to be brutal.

Which goes a long way toward explaining why everyone–from Time Warner’s Time Inc. (TWX) to GE’s (GE) NBC to every Web start-up you can think of–is looking at dwindling ad revenue for the foreseeable future.

And yes, you can point your finger most accusingly at Detroit, if that makes you feel better: While some imports, like Toyota (TM) and Honda (HMC), actually kept spending steady or increased it, the formerly Big 3 all made big cuts. General Motors (GM), the country’s biggest auto ad buyer, dropped spending six percent; Ford (F) and Chrysler dropped 22 percent each.

MediaPost has the full gory details.

[Image Credit: Hauke Sandhaus]