It’s interesting that despite the fact that WAN optimization has gained a lot of visibility over the last 4+ years, there are still some generalization about the technology that prospective buyers need to be better educated on. Take this story in Network World today on the topic of WAN optimization having good upside in the current depressed economy.While the “upsides” of reduced WAN costs are well covered — especially as traffic volume continues to grow through VoIP, video, etc — the one caveat called out is “lack of visibility”, with the recommendation of “IT organizations should think twice about doing that if it means they lose visibility into what is happening on their network.”I certainly agree that some WOC products do kill visibility into network traffic and related IP services, as previous customer examples have shown in Network World and other publications (and yes, these occurances still happen 2 years later). However, it’s important for potential buyers to understand that not all vendors’ products destroy network visibility through “tunneling”. Cisco, Expand and some other vendors carefully designed their products to avoid this issue of impacting network visibility and resulting monitoring, QoS/VoIP, filtering/security and other services.In summary, prospective buyers of WAN optimization equipment should first assess how important is retaining visibility to the network traffic being optimized, and then adjust their list of target vendors based on that factor. But they shouldn’t wholesale “think twice about doing that” — just select the right solution given their needs — as this technology clearly has business upsides to justify a new project, even in this depressed economy.