LinkedIn announced 100 million members (with a great infographic) earlier this week and look to be on track for an IPO in the second quarter. The company is profitable, growing, and for the moment, on top of business social media networking. For B2B marketers, LinkedIn cannot be ignored.

Does LinkedIn have a defensible advantage as a B2B media player as they go into an IPO? Will the advertisers driving marketing revenue (approximately one-third of LinkedIn’s revenue) see results and continue investing?

Across multiple clients, LinkedIn has consistently performed well. One thing that has stood out is the engagement of LinkedIn traffic. Whether measuring page views per visit, time on site, or registration rate, LinkedIn has delivered above average results every time.

Here are five reasons I believe LinkedIn has performed well, and what it means for LinkedIn’s future as a B2B media powerhouse.

• Targeting Data. LinkedIn has tremendous B2B data for targeting advertising. Accurate professional profiles, maintained by each of us, group membership, even a business social graph (check out InMaps). For many B2B marketers, the data is more relevant than Facebook. When compared to vertical trade sites, LinkedIn can eliminate the vendor, marketing and sales traffic that represents a sizable portion of many audiences. Since data is collected and used for targeting within LinkedIn, online advertising regulation would likely benefit, not harm, LinkedIn.
• Uncluttered Ad Space. The LinkedIn homepage only has one prominent (and respectfully sized) ad unit and one text link. Advertising stands out rather than getting lost in competing site and advertising clutter, while the primary function of LinkedIn remains front and center. Although this would be easy for competitors to emulate, the trend is to more intrusive and more cluttered ad environments in B2B. Resisting this trend is benefiting LinkedIn.
• Business Leisure Time. LinkedIn is professional, but it isn’t on deadline. Sharing content, confirming or inviting connections, or posting questions is a business and professional activity, done in a free moment. A business mindset with a moment to spare is an unusual situation, and is an advantage for advertisers looking to engage, not just reach, audiences. This, combined with targeting, likely explains the above-average engagement referenced above from LinkedIn campaigns.
• Self-contained Programs. With company pages and groups, campaigns can run within LinkedIn. Although Facebook will continue to challenge LinkedIn as a place to build business-focused communities, LinkedIn is way ahead of other B2B media companies. However, one note of caution here: most LinkedIn campaigns are not integrated enough today to take advantage of this, and the campaigns promoting groups are generally the least targeted campaigns I see on LinkedIn. Companies may be trying to scale these programs too far, and in doing so, are losing the targeting advantages of LinkedIn.
• Cost Efficiency. LinkedIn may not compete favorably on price with Facebook or Google for pure DR campaigns, but considering the uncluttered space, targeting and engagement, LinkedIn advertising rates are very competitive. I see more ads on LinkedIn that are clearly targeted to me, professionally, than on any other site I visit. Keeping prices competitive in order to sell targeted ad space appears to be a strategic decision LinkedIn has made, to the benefit of all advertisers.

Sure, you can have too much of a good thing. But as long as advertisers ensure the points above are working for them, I believe LinkedIn advertisers will be successful and LinkedIn will be a top B2B media company. Now to find a way to get in on the IPO.